MyBatis 基础

 

@Select("select * from t_person where id = #{id}")
Person selectPersonById(Integer id);

@Select("<script>
select * from t_person where id = #{id}
<when test='address !=null'> and address = #{address}
</when>
</script>")
Person selectPersonById(Integer id， String address);

 

指定填入 

 @TableField(fill = FieldFill.INSERT_UPDATE)

public class DefaultDBFieldHandler implements MetaObjectHandler   // 芋道 jh-spring-boot-starter-mybatis

 

List 类型 存储

    TypeHandler    // 芋道 中查询

    @TableField(typeHandler = JacksonTypeHandler.class)   字段变量上 加上  //I

    @TableName(value="check_type", autoResultMap = true).   DO 类需要加上 autoResultMap  否则 读取为 null      // II

    @Select("SELECT * FROM lihu.clinic_room where room_id=#{roomId} and bed_no=#{bedNo}")
    @Results({
      @Result(property = "checkTypes", column = "check_types", typeHandler=com.baomidou.mybatisplus.extension.handlers.JacksonTypeHandler.class)   // III
    })
    RoomDO getRoom(@Param("roomId")Long roomId, @Param("bedNo")String bedNo);

NULL值字段 也写入

 @TableField(updateStrategy = FieldStrategy.ALWAYS)